1. Field of the Invention
This invention relates to ferromagnetic memory and more specifically to ferromagnetic memory utilizing giant magnetoresistance and spin polarization in annular memory elements.
2. Description of the Related Art
In U.S. Pat. No. 5,541,868 an annular GMR-based memory element is disclosed. The description tells how to construct a magnetic memory element using the giant magnetoresistance effect with the current passing perpendicular to the plane of the device. The disclosure does not, however, describe an optimal circuit architecture employing those elements, nor does it discuss how many different approaches to reading and writing may be realized by employing different supporting circuits.
3. Objects of the Invention
It is an object of this invention to provide a magnetic random access memory which is scalable to greater than 1 gigabit/cm.sup.2 density.
It is a further object of this invention to provide a magnetic random access memory which has fast switching elements which are capable of switching at less than 10 nanoseconds.
It is a further object of this invention to provide a magnetic random access memory which has a wide temperature tolerance of from -150.degree. C. to +150.degree. C.
It is a further object of this invention to provide a magnetic random access memory which can be made by a low cost fabrication technique such as sputtered metal films on silicon.
It is a further object of this invention to provide a magnetic random access memory with a bit line in addition to a sense line and a word line to add flexibility to the magnetic switching and bit addressability.
It is a further object of this invention to provide a magnetic random access memory which has a bit line in addition to a sense line and a word line so that the current through the sense line is not needed for manipulating the magnetic state of the memory element.
These and further objects of the invention will become apparent as the description of the invention proceeds.